1. Field of the Invention
Invention relates to quantitative measurements of the functional activity of human beings.
2. Description of the Related Art
All rehabilitation professionals share a need to measure outcome and produce "hard data" on the effectiveness of the therapy. Most of the available instruments described in the literature are pencil and paper questionnaires, which give a qualitative measure on dependence in specific activities.
Rehabilitation programs and facilities need a way to measure objectively the extent of physical activity of the mentally and physically disabled. This appraisal of functional status can be used to find compatible occupations allowing for specific impairments. Available measuring devices measure limited aspects of daily functioning, but no prior art instrument is available that records the overall pattern of daily physical activities using mobility and motion criteria.
Representative of the prior art is U.S. Pat. No. 4,729,377, issued to Church et al. on Mar. 8, 1988, which discloses a garment containing multiple conductive paths made of conductive cloth. The invention is used to contact an external electrical apparatus to various points on the skin for monitoring by soaking the site with conducting fluid. As shown in the advertising materials of Bio-Stimu Trend Corp., the assignee of the above-referenced patent, the invention is designed to measure activity in isolated joints or limbs. Moreover the use of conducting fluid for electrode connection makes the invention inappropriate for long term wearing use or a total body measurement of activity.
U.S. Pat. No. 4,862,896, issued to Greenwold et al. on Sep. 5, 1989, discloses a heart monitoring device for use under emergency conditions. Again, this device makes use of electrodes that are placed next to the skin requiring a fluid or paste to establish electrical conduction for the measurement of activity.
A more invasive technique is disclosed in U.S. Pat. No. 4,685,466, issued to Rau on Aug. 11, 1987. Rau discloses a measuring sensor using a plurality of short needle points to penetrate into the uppermost cell layers of the horny skin. The sensor is retained by means of a preferable flexible mounting. A quasi-invasive technique is not conducive to long term wearing nor able to quantify the electro-physiological parameters for an entire body.
Still another method for measuring the electrical activity in a patient's body is disclosed in U.S. Pat. No. 4,354,509, issued to Strahwald et al. on Oct. 19, 1982. This invention features an electrode system comprising flexible formed parts. In this disclosure, the contacting agent is a fleece material with an external contour slightly greater than the exterior perimeter of the formed part of the electrode system. As in the previously discussed disclosures, the concept is to make electrical contact with the skin of the patient.
The Social Security Administration recognized the strong need to develop techniques that would improve the lifestyles and working conditions of the physically challenged population. Olander et al. (Olander B. Walker, and G. Prazak, "An Agenda for Excellence," Journal of Rehabilitation, pp. 17-18, Mar. 1990) discussed this object in their publication "An Agenda for Excellence". The authors point out the need to improve the quality of current rehabilitation programs that are designed to place physically challenged persons into the workforce. In their study of rehabilitation programs throughout the country, they found that the top programs had a fifty percent successful placement ratio. In contrast, the worst programs achieved only a sixteen percent successful placement. One of the problems was considered to be a "lack of sufficient objective data to help evaluate the efficiency and effectiveness of their approaches". In a paper entitled "Vocational Evaluation in Supported Employment" by Rogan and Hagner (P. Rogan and D. Hagner, "Vocational Evaluation in Supported Employment," Journal of Rehabilitation, pp. 45-50, Mar. 1990), the authors discuss the criteria for vocational evaluation comprising "(a) describing an individual by his or her functioning needs, (b) specifying the outcomes to be achieved through rehabilitation, and (c) identifying the interventions and services required to achieve those outcomes". They concluded that "the context in which assessment occurs should be a primary importance. That is, behavior should be assessed within the same settings in which it is ultimately expected to occur."
A few devices have been developed which measure limited body movements. A wheelchair odometer, developed by Halstead et al. (L.S. Halstead, "Longitudinal Unobtrusive Measurements in Rehabilitation," Arch. Phys. Med. Regabil., vol. 57, pp. 189-193, 1976), measures distances traveled by wheelchair bound persons. Halstead (L.S. Halstead et al., "Spinal Cord Injury: Time Out of bed During Rehabilitation," Arch. Phys. Med. Rehabil., vol. 60, pp. 590-595, 1979) and Sanders (S. H. Sanders, "Toward a Practical Instrument System for the Automatic Measurement of "up-time" in Chronic Back Pain Patients," Pain, vol. 9, pp. 103-109, 1980) both explored the use of bed rest indicators that show how often a patient's bed was being occupied. A device capable of determining the amount of time spent in either a horizontal or vertical position, using a mechanical device attached to the trunk of the patient, was discussed by Bloom et al. (W. L. Bloom and M. F. Eidex, "Inactivity as a Major Factor in Obesity," Metabolism, vol. 16, pp. 679-684, 1967). LePorte et al. (R. E. LePorte et al., "An Objective Measure of Physical Activity for Epidemiology," Res. Am J Epidemiol, vol. 109, pp. 158-168, 1979) disclosed a surface EMG monitoring system that measures motor activity in human subjects. All of the above devices were insensitive to sleeping positions, physically cumbersome, difficult to wear and could be used for only a limited amount of time.
There have been many others who have concentrated their efforts on further analyzing back movement. Ortengren and Andersson (B. J. Anderson and D. B. Chaffin, Occupational Biomechanics. Wiley-Interscience, pp. 258-259, 1984) developed one such device which measures trunk flexion. The instrument consists of a pendulum potentiometer, a five level A to D converter, control circuits, and digital registers positioned onto a small harness to be worn on the back. This particular analyzer records amount of time spent in various intervals of forward flexion, as well as the number of times in and out of each interval. This device, however, is capable of measuring only forward trunk movements in the sagittal plane. Another device (. J. Anderson and D. B. Chaffin, Occupational Biomechanics. Wiley-Interscience, p. 138, 1984), the radio pill, is able to measure back movement. It is a pressure sensitive device that is swallowed. This procedure is expensive, intrusive and provides limited results.
Another approach disclosed by Brown, (L.P. Brown, "The Theory and Design of Piezoelectric/Pyroelectric Polymer Film Sensors for Biomedical Engineering Applications," Biomedical Science Instrumentation, vol. 25, pp. 119-126, 1989) uses piezo/pyroelectricity polymer film sensors. These sensors are capable of detecting numerical change in coordinates by detecting voltage fluctuations for a particular body location. The polymer film sensors tend to be capacitive, meaning that if a particular body position is held for a substantial length of time, the capacitive nature would result in loss of information.
None of the aforementioned devices are capable of measuring overall general body movement for an extended continuous time.